Abstract: Exosome is a kind of immune functional membrane vesicles secreted from multivesicular body fusing with cell membrane. It contains a large number of closely related functional protein and lipid components, with the functions of cell growth proteins waste removal, signal transduction, antigen presentation, cells activation, inducing and enhancing immune response. In recent years, some researchers used exosomes as nanocarriers to avoid the possible side-effects and immune rejection of usual exogenous nanocarriers. This review briefly describes its discovery, function and development as a drug carrier with reference to some recent research papers to replenish a novel drug delivery system.